Pixar's RenderMan is a lasting effect

Rendering software celebrates its 20th anniversary

Pixar Animation's rendering software first was published two decades ago, and since then it has helped usher in the era of computer graphics in filmmaking.

The core technology that led to RenderMan was created by Pixar co-founder and president Ed Catmull, co-founder and chief scientist Loren Carpenter and vp software engineering Rob Cook.

"At that time, CG was nowhere in the special effects business," said Catmull, who will be the featured speaker today at Siggraph, the computer graphics confab, where the newest version of RenderMan will be unveiled. "Special effects were done practically or with models."

Many have worked to advance the application during the past 20 years. RenderMan has contributed to all of Pixar's CG feature titles as well as to countless additional animated and VFX-driven films, including "The Abyss," "Jurassic Park," "Titanic," "The Lord of the Rings" trilogy and the "Pirates of the Caribbean" films.

Rendering is the process of calculating the information in a CG file for final video output -- essentially turning numbers into images.

In March 2001, Catmull, Carpenter and Cook received an Academy Award of Merit -- an Oscar statuette -- for the advancements in motion picture rendering exemplified in RenderMan. It was the first Oscar awarded for a software package.

"It enabled many movies to be made, so it was a tremendously important development," said VFX veteran Richard Edlund, chair of the Academy's Scientific and Technical Awards Committee whose honors include four Oscars for VFX and three Scientific and Engineering Awards.

Catmull said there were several key drivers in RenderMan's development.

"In order to fit into live action, we needed to solve the problem of motion blur (the streaking of a moving object)," he said. "Also, we need a mechanism for the artist to be able to control the look and the lighting."

He added: "Then we made a decision which proved to be an important one. We decided that while we were leaders in animation -- we were working on 'Toy Story' at the time -- we were going to sell a commercial product, and we would let the studios drive the direction of where RenderMan went."

A key early customer was Lucasfilm's Industrial Light + Magic. (Pixar originally was a division of Lucasfilm before it was bought by Steve Jobs.)

"By letting ILM, Digital Domain and other studios have input, we had this incredible breadth of really high-end, artistically demanding people who were requiring more and more complex images," Catmull said.

He said two films marked turns in the road for the software: 1991's "Terminator 2: Judgment Day" and 1993's "Jurassic Park."

" 'Terminator 2' made a lot of money and used RenderMan," Catmull said. "That got a lot of people moving down the road of using RenderMan and computer graphics in making films.

"Two years later, 'Jurassic Park' came out. That was a huge film. Whatever resistance there was to this new direction essentially changed. When that movie came out, it was like a huge awakening in the industry. Effects were moving into a new era -- the era of computer graphics."

Said Edlund: "What was so great about 'Jurassic Park' was that the dinosaurs had motion blur, so they looked natural. If you compare 'Jurassic Park' with the earlier dinosaur stop-motion movies, where the dinosaurs would judder around when they were moving quickly, that lost the sense of reality."

Renderers were complicated when RenderMan was first published, said WETA VFX supervisor Joe Letteri, who earned Oscars for the second and third "Lord of the Rings" films as well as for "King Kong."

"RenderMan was something you could do rendering with that was programmable," he said.

He likened using the application to "being able to drive a nice car without worrying about how to build the engine. We could just focus on the look that we wanted to get and not worry so much what was going on internally in the engine. That was pretty breakthrough at the time.

"We've used RenderMan on all three 'Rings' films, on "Kong' -- the bulk of our rendering is done on RenderMan," Letteri said. "As the things that we've been trying to do have become more complicated, Pixar has just been there with us, trying to make sure those things are achievable."